The present invention relates generally to tractor-loaders having a loader apparatus mounted forwardly of the tractor, and, more particularly, to a control mechanism for incorporating three control functions of the loader apparatus into one control device.
Tractor-loaders are provided with a loader mechanism pivotally connected to the frame of the tractor and movable through manipulation of hydraulic lift cylinders and bucket tilt cylinders to effect operation of the loader mechanism forwardly of the tractor. The loader mechanism typically includes a working tool mounted at the distal end of longitudinally extending loader arms Which is pivotally connected thereto and operable through manipulation of the bucket tilt cylinders to move relative to the loader arms. Some loader mechanisms incorporate an auxiliary device such as a clam shell bucket which requires a third actuator to effect the respective movement thereof.
Typical control devices for loader mechanism provide for movement of a control lever fore and aft in a longitudinal direction to control the raising and lowering of the loader arms and a transverse, back and forth motion of the same control lever to control the roll of the bucket relative to the loader arms. Auxiliary device controls are usually operated through a separate control lever and associated linkage to actuate a third spool on the tractor hydraulic valve. Such auxiliary controls become cumbersome to operate simultaneously with the raising, lowering, and tilting of the loader mechanism through manipulation of the loader control lever. Accordingly, it would be desirable to provide a single control lever capable of effecting control of both the loader lift cylinders and the bucket tilt cylinders, as well as being capable of effecting control of an auxiliary device associated with the loader mechanism.